/* merged revision: 5b951d74bd66ec9d38448e0a85b1cf8b85d97db3 */
/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */
#ifndef CROW_http_parser_h
#define CROW_http_parser_h
#ifdef __cplusplus
extern "C" {
#endif

/* Also update SONAME in the Makefile whenever you change these. */
#define CROW_HTTP_PARSER_VERSION_MAJOR 2
#define CROW_HTTP_PARSER_VERSION_MINOR 3
#define CROW_HTTP_PARSER_VERSION_PATCH 0

#include <sys/types.h>
#if defined(_WIN32) && !defined(__MINGW32__) && (!defined(_MSC_VER) || _MSC_VER<1600)
#include <BaseTsd.h>
#include <stddef.h>
typedef __int8 int8_t;
typedef unsigned __int8 uint8_t;
typedef __int16 int16_t;
typedef unsigned __int16 uint16_t;
typedef __int32 int32_t;
typedef unsigned __int32 uint32_t;
typedef __int64 int64_t;
typedef unsigned __int64 uint64_t;
#else
#include <stdint.h>
#endif

/* Compile with -DHTTP_PARSER_STRICT=0 to make less checks, but run
 * faster
 */
#ifndef CROW_HTTP_PARSER_STRICT
# define CROW_HTTP_PARSER_STRICT 1
#endif

/* Maximium header size allowed. If the macro is not defined
 * before including this header then the default is used. To
 * change the maximum header size, define the macro in the build
 * environment (e.g. -DHTTP_MAX_HEADER_SIZE=<value>). To remove
 * the effective limit on the size of the header, define the macro
 * to a very large number (e.g. -DHTTP_MAX_HEADER_SIZE=0x7fffffff)
 */
#ifndef CROW_HTTP_MAX_HEADER_SIZE
# define CROW_HTTP_MAX_HEADER_SIZE (80*1024)
#endif

typedef struct http_parser http_parser;
typedef struct http_parser_settings http_parser_settings;

/* Callbacks should return non-zero to indicate an error. The parser will
 * then halt execution.
 *
 * The one exception is on_headers_complete. In a HTTP_RESPONSE parser
 * returning '1' from on_headers_complete will tell the parser that it
 * should not expect a body. This is used when receiving a response to a
 * HEAD request which may contain 'Content-Length' or 'Transfer-Encoding:
 * chunked' headers that indicate the presence of a body.
 *
 * http_data_cb does not return data chunks. It will be call arbitrarally
 * many times for each string. E.G. you might get 10 callbacks for "on_url"
 * each providing just a few characters more data.
 */
typedef int (*http_data_cb)(http_parser*, const char *at, size_t length);
typedef int (*http_cb)(http_parser*);

/* Request Methods */
#define CROW_HTTP_METHOD_MAP(CROW_XX)         \
  CROW_XX(0,  DELETE,      DELETE)       \
  CROW_XX(1,  GET,         GET)          \
  CROW_XX(2,  HEAD,        HEAD)         \
  CROW_XX(3,  POST,        POST)         \
  CROW_XX(4,  PUT,         PUT)          \
  /* pathological */                \
  CROW_XX(5,  CONNECT,     CONNECT)      \
  CROW_XX(6,  OPTIONS,     OPTIONS)      \
  CROW_XX(7,  TRACE,       TRACE)        \
  /* webdav */                      \
  CROW_XX(8,  COPY,        COPY)         \
  CROW_XX(9,  LOCK,        LOCK)         \
  CROW_XX(10, MKCOL,       MKCOL)        \
  CROW_XX(11, MOVE,        MOVE)         \
  CROW_XX(12, PROPFIND,    PROPFIND)     \
  CROW_XX(13, PROPPATCH,   PROPPATCH)    \
  CROW_XX(14, SEARCH,      SEARCH)       \
  CROW_XX(15, UNLOCK,      UNLOCK)       \
  /* subversion */                  \
  CROW_XX(16, REPORT,      REPORT)       \
  CROW_XX(17, MKACTIVITY,  MKACTIVITY)   \
  CROW_XX(18, CHECKOUT,    CHECKOUT)     \
  CROW_XX(19, MERGE,       MERGE)        \
  /* upnp */                        \
  CROW_XX(20, MSEARCH,     M-SEARCH)     \
  CROW_XX(21, NOTIFY,      NOTIFY)       \
  CROW_XX(22, SUBSCRIBE,   SUBSCRIBE)    \
  CROW_XX(23, UNSUBSCRIBE, UNSUBSCRIBE)  \
  /* RFC-5789 */                    \
  CROW_XX(24, PATCH,       PATCH)        \
  CROW_XX(25, PURGE,       PURGE)        \
  /* CalDAV */                      \
  CROW_XX(26, MKCALENDAR,  MKCALENDAR)   \

enum http_method {
#define CROW_XX(num, name, string) HTTP_##name = num,
    CROW_HTTP_METHOD_MAP(CROW_XX)
#undef CROW_XX
}    ;

    enum http_parser_type {HTTP_REQUEST, HTTP_RESPONSE, HTTP_BOTH};

    /* Flag values for http_parser.flags field */
    enum flags
    {   F_CHUNKED = 1 << 0
        , F_CONNECTION_KEEP_ALIVE = 1 << 1
        , F_CONNECTION_CLOSE = 1 << 2
        , F_TRAILING = 1 << 3
        , F_UPGRADE = 1 << 4
        , F_SKIPBODY = 1 << 5
    };

    /* Map for errno-related constants
     *
     * The provided argument should be a macro that takes 2 arguments.
     */
#define CROW_HTTP_ERRNO_MAP(CROW_XX)                                           \
  /* No error */                                                     \
  CROW_XX(OK, "success")                                                  \
                                                                     \
  /* Callback-related errors */                                      \
  CROW_XX(CB_message_begin, "the on_message_begin callback failed")       \
  CROW_XX(CB_url, "the on_url callback failed")                           \
  CROW_XX(CB_header_field, "the on_header_field callback failed")         \
  CROW_XX(CB_header_value, "the on_header_value callback failed")         \
  CROW_XX(CB_headers_complete, "the on_headers_complete callback failed") \
  CROW_XX(CB_body, "the on_body callback failed")                         \
  CROW_XX(CB_message_complete, "the on_message_complete callback failed") \
  CROW_XX(CB_status, "the on_status callback failed")                     \
                                                                     \
  /* Parsing-related errors */                                       \
  CROW_XX(INVALID_EOF_STATE, "stream ended at an unexpected time")        \
  CROW_XX(HEADER_OVERFLOW,                                                \
     "too many header bytes seen; overflow detected")                \
  CROW_XX(CLOSED_CONNECTION,                                              \
     "data received after completed connection: close message")      \
  CROW_XX(INVALID_VERSION, "invalid HTTP version")                        \
  CROW_XX(INVALID_STATUS, "invalid HTTP status code")                     \
  CROW_XX(INVALID_METHOD, "invalid HTTP method")                          \
  CROW_XX(INVALID_URL, "invalid URL")                                     \
  CROW_XX(INVALID_HOST, "invalid host")                                   \
  CROW_XX(INVALID_PORT, "invalid port")                                   \
  CROW_XX(INVALID_PATH, "invalid path")                                   \
  CROW_XX(INVALID_QUERY_STRING, "invalid query string")                   \
  CROW_XX(INVALID_FRAGMENT, "invalid fragment")                           \
  CROW_XX(LF_EXPECTED, "CROW_LF character expected")                           \
  CROW_XX(INVALID_HEADER_TOKEN, "invalid character in header")            \
  CROW_XX(INVALID_CONTENT_LENGTH,                                         \
     "invalid character in content-length header")                   \
  CROW_XX(INVALID_CHUNK_SIZE,                                             \
     "invalid character in chunk size header")                       \
  CROW_XX(INVALID_CONSTANT, "invalid constant string")                    \
  CROW_XX(INVALID_INTERNAL_STATE, "encountered unexpected internal state")\
  CROW_XX(STRICT, "strict mode assertion failed")                         \
  CROW_XX(PAUSED, "parser is paused")                                     \
  CROW_XX(UNKNOWN, "an unknown error occurred")

    /* Define HPE_* values for each errno value above */
#define CROW_HTTP_ERRNO_GEN(n, s) HPE_##n,
    enum http_errno {
        CROW_HTTP_ERRNO_MAP(CROW_HTTP_ERRNO_GEN)
    };
#undef CROW_HTTP_ERRNO_GEN

    /* Get an http_errno value from an http_parser */
#define CROW_HTTP_PARSER_ERRNO(p)            ((enum http_errno) (p)->http_errno)

    struct http_parser {
        /** PRIVATE **/
        unsigned int type : 2; /* enum http_parser_type */
        unsigned int flags : 6; /* F_* values from 'flags' enum; semi-public */
        unsigned int state : 8; /* enum state from http_parser.c */
        unsigned int header_state : 8; /* enum header_state from http_parser.c */
        unsigned int index : 8; /* index into current matcher */

        uint32_t nread; /* # bytes read in various scenarios */
        uint64_t content_length; /* # bytes in body (0 if no Content-Length header) */

        /** READ-ONLY **/
        unsigned short http_major;
        unsigned short http_minor;
        unsigned int status_code : 16; /* responses only */
        unsigned int method : 8; /* requests only */
        unsigned int http_errno : 7;

        /* 1 = Upgrade header was present and the parser has exited because of that.
         * 0 = No upgrade header present.
         * Should be checked when http_parser_execute() returns in addition to
         * error checking.
         */
        unsigned int upgrade : 1;

        /** PUBLIC **/
        void *data; /* A pointer to get hook to the "connection" or "socket" object */
    };

    struct http_parser_settings {
        http_cb on_message_begin;
        http_data_cb on_url;
        http_data_cb on_status;
        http_data_cb on_header_field;
        http_data_cb on_header_value;
        http_cb on_headers_complete;
        http_data_cb on_body;
        http_cb on_message_complete;
    };

    enum http_parser_url_fields
    {   UF_SCHEMA = 0
        , UF_HOST = 1
        , UF_PORT = 2
        , UF_PATH = 3
        , UF_QUERY = 4
        , UF_FRAGMENT = 5
        , UF_USERINFO = 6
        , UF_MAX = 7
    };

    /* Result structure for http_parser_parse_url().
     *
     * Callers should index into field_data[] with UF_* values iff field_set
     * has the relevant (1 << UF_*) bit set. As a courtesy to clients (and
     * because we probably have padding left over), we convert any port to
     * a uint16_t.
     */
    struct http_parser_url {
        uint16_t field_set; /* Bitmask of (1 << UF_*) values */
        uint16_t port; /* Converted UF_PORT string */

        struct {
            uint16_t off; /* Offset into buffer in which field starts */
            uint16_t len; /* Length of run in buffer */
        }field_data[UF_MAX];
    };

    /* Returns the library version. Bits 16-23 contain the major version number,
     * bits 8-15 the minor version number and bits 0-7 the patch level.
     * Usage example:
     *
     *   unsigned long version = http_parser_version();
     *   unsigned major = (version >> 16) & 255;
     *   unsigned minor = (version >> 8) & 255;
     *   unsigned patch = version & 255;
     *   printf("http_parser v%u.%u.%u\n", major, minor, version);
     */
    unsigned long http_parser_version(void);

    void http_parser_init(http_parser *parser, enum http_parser_type type);

    size_t http_parser_execute(http_parser *parser,
    const http_parser_settings *settings,
    const char *data,
    size_t len);

    /* If http_should_keep_alive() in the on_headers_complete or
     * on_message_complete callback returns 0, then this should be
     * the last message on the connection.
     * If you are the server, respond with the "Connection: close" header.
     * If you are the client, close the connection.
     */
    int http_should_keep_alive(const http_parser *parser);

    /* Returns a string version of the HTTP method. */
    const char *http_method_str(enum http_method m);

    /* Return a string name of the given error */
    const char *http_errno_name(enum http_errno err);

    /* Return a string description of the given error */
    const char *http_errno_description(enum http_errno err);

    /* Parse a URL; return nonzero on failure */
    int http_parser_parse_url(const char *buf, size_t buflen,
    int is_connect,
    struct http_parser_url *u);

    /* Pause or un-pause the parser; a nonzero value pauses */
    void http_parser_pause(http_parser *parser, int paused);

    /* Checks if this is the final chunk of the body. */
    int http_body_is_final(const http_parser *parser);

    /*#include "http_parser.h"*/
    /* Based on src/http/ngx_http_parse.c from NGINX copyright Igor Sysoev
     *
     * Additional changes are licensed under the same terms as NGINX and
     * copyright Joyent, Inc. and other Node contributors. All rights reserved.
     *
     * Permission is hereby granted, free of charge, to any person obtaining a copy
     * of this software and associated documentation files (the "Software"), to
     * deal in the Software without restriction, including without limitation the
     * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
     * sell copies of the Software, and to permit persons to whom the Software is
     * furnished to do so, subject to the following conditions:
     *
     * The above copyright notice and this permission notice shall be included in
     * all copies or substantial portions of the Software.
     *
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
     * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
     * IN THE SOFTWARE.
     */
#include <assert.h>
#include <stddef.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>

#ifndef CROW_ULLONG_MAX
# define CROW_ULLONG_MAX ((uint64_t) -1) /* 2^64-1 */
#endif

#ifndef CROW_MIN
# define CROW_MIN(a,b) ((a) < (b) ? (a) : (b))
#endif

#ifndef CROW_ARRAY_SIZE
# define CROW_ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
#endif

#ifndef CROW_BIT_AT
# define CROW_BIT_AT(a, i)                                                \
  (!!((unsigned int) (a)[(unsigned int) (i) >> 3] &                  \
   (1 << ((unsigned int) (i) & 7))))
#endif

#ifndef CROW_ELEM_AT
# define CROW_ELEM_AT(a, i, v) ((unsigned int) (i) < CROW_ARRAY_SIZE(a) ? (a)[(i)] : (v))
#endif

#define CROW_SET_ERRNO(e)                                                 \
do {                                                                 \
  parser->http_errno = (e);                                          \
} while(0)

    /* Run the notify callback FOR, returning ER if it fails */
#define CROW_CALLBACK_NOTIFY_(FOR, ER)                                    \
do {                                                                 \
  assert(CROW_HTTP_PARSER_ERRNO(parser) == HPE_OK);                       \
                                                                     \
  if (settings->on_##FOR) {                                          \
    if (0 != settings->on_##FOR(parser)) {                           \
      CROW_SET_ERRNO(HPE_CB_##FOR);                                       \
    }                                                                \
                                                                     \
    /* We either errored above or got paused; get out */             \
    if (CROW_HTTP_PARSER_ERRNO(parser) != HPE_OK) {                       \
      return (ER);                                                   \
    }                                                                \
  }                                                                  \
} while (0)

    /* Run the notify callback FOR and consume the current byte */
#define CROW_CALLBACK_NOTIFY(FOR)            CROW_CALLBACK_NOTIFY_(FOR, p - data + 1)

    /* Run the notify callback FOR and don't consume the current byte */
#define CROW_CALLBACK_NOTIFY_NOADVANCE(FOR)  CROW_CALLBACK_NOTIFY_(FOR, p - data)

    /* Run data callback FOR with LEN bytes, returning ER if it fails */
#define CROW_CALLBACK_DATA_(FOR, LEN, ER)                                 \
do {                                                                 \
  assert(CROW_HTTP_PARSER_ERRNO(parser) == HPE_OK);                       \
                                                                     \
  if (FOR##_mark) {                                                  \
    if (settings->on_##FOR) {                                        \
      if (0 != settings->on_##FOR(parser, FOR##_mark, (LEN))) {      \
        CROW_SET_ERRNO(HPE_CB_##FOR);                                     \
      }                                                              \
                                                                     \
      /* We either errored above or got paused; get out */           \
      if (CROW_HTTP_PARSER_ERRNO(parser) != HPE_OK) {                     \
        return (ER);                                                 \
      }                                                              \
    }                                                                \
    FOR##_mark = NULL;                                               \
  }                                                                  \
} while (0)

    /* Run the data callback FOR and consume the current byte */
#define CROW_CALLBACK_DATA(FOR)                                           \
    CROW_CALLBACK_DATA_(FOR, p - FOR##_mark, p - data + 1)

    /* Run the data callback FOR and don't consume the current byte */
#define CROW_CALLBACK_DATA_NOADVANCE(FOR)                                 \
    CROW_CALLBACK_DATA_(FOR, p - FOR##_mark, p - data)

    /* Set the mark FOR; non-destructive if mark is already set */
#define CROW_MARK(FOR)                                                    \
do {                                                                 \
  if (!FOR##_mark) {                                                 \
    FOR##_mark = p;                                                  \
  }                                                                  \
} while (0)

#define CROW_PROXY_CONNECTION "proxy-connection"
#define CROW_CONNECTION "connection"
#define CROW_CONTENT_LENGTH "content-length"
#define CROW_TRANSFER_ENCODING "transfer-encoding"
#define CROW_UPGRADE "upgrade"
#define CROW_CHUNKED "chunked"
#define CROW_KEEP_ALIVE "keep-alive"
#define CROW_CLOSE "close"

    enum state
    {   s_dead = 1 /* important that this is > 0 */

        , s_start_req_or_res
        , s_res_or_resp_H
        , s_start_res
        , s_res_H
        , s_res_HT
        , s_res_HTT
        , s_res_HTTP
        , s_res_first_http_major
        , s_res_http_major
        , s_res_first_http_minor
        , s_res_http_minor
        , s_res_first_status_code
        , s_res_status_code
        , s_res_status_start
        , s_res_status
        , s_res_line_almost_done

        , s_start_req

        , s_req_method
        , s_req_spaces_before_url
        , s_req_schema
        , s_req_schema_slash
        , s_req_schema_slash_slash
        , s_req_server_start
        , s_req_server
        , s_req_server_with_at
        , s_req_path
        , s_req_query_string_start
        , s_req_query_string
        , s_req_fragment_start
        , s_req_fragment
        , s_req_http_start
        , s_req_http_H
        , s_req_http_HT
        , s_req_http_HTT
        , s_req_http_HTTP
        , s_req_first_http_major
        , s_req_http_major
        , s_req_first_http_minor
        , s_req_http_minor
        , s_req_line_almost_done

        , s_header_field_start
        , s_header_field
        , s_header_value_discard_ws
        , s_header_value_discard_ws_almost_done
        , s_header_value_discard_lws
        , s_header_value_start
        , s_header_value
        , s_header_value_lws

        , s_header_almost_done

        , s_chunk_size_start
        , s_chunk_size
        , s_chunk_parameters
        , s_chunk_size_almost_done

        , s_headers_almost_done
        , s_headers_done

        /* Important: 's_headers_done' must be the last 'header' state. All
         * states beyond this must be 'body' states. It is used for overflow
         * checking. See the CROW_PARSING_HEADER() macro.
         */

        , s_chunk_data
        , s_chunk_data_almost_done
        , s_chunk_data_done

        , s_body_identity
        , s_body_identity_eof

        , s_message_done
    };

#define CROW_PARSING_HEADER(state) (state <= s_headers_done)

    enum header_states
    {   h_general = 0
        , h_C
        , h_CO
        , h_CON

        , h_matching_connection
        , h_matching_proxy_connection
        , h_matching_content_length
        , h_matching_transfer_encoding
        , h_matching_upgrade

        , h_connection
        , h_content_length
        , h_transfer_encoding
        , h_upgrade

        , h_matching_transfer_encoding_chunked
        , h_matching_connection_keep_alive
        , h_matching_connection_close

        , h_transfer_encoding_chunked
        , h_connection_keep_alive
        , h_connection_close
    };

    enum http_host_state
    {
        s_http_host_dead = 1
        , s_http_userinfo_start
        , s_http_userinfo
        , s_http_host_start
        , s_http_host_v6_start
        , s_http_host
        , s_http_host_v6
        , s_http_host_v6_end
        , s_http_host_port_start
        , s_http_host_port
    };

    /* Macros for character classes; depends on strict-mode  */
#define CROW_CR                  '\r'
#define CROW_LF                  '\n'
#define CROW_LOWER(c)            (unsigned char)(c | 0x20)
#define CROW_IS_ALPHA(c)         (CROW_LOWER(c) >= 'a' && CROW_LOWER(c) <= 'z')
#define CROW_IS_NUM(c)           ((c) >= '0' && (c) <= '9')
#define CROW_IS_ALPHANUM(c)      (CROW_IS_ALPHA(c) || CROW_IS_NUM(c))
#define CROW_IS_HEX(c)           (CROW_IS_NUM(c) || (CROW_LOWER(c) >= 'a' && CROW_LOWER(c) <= 'f'))
#define CROW_IS_MARK(c)          ((c) == '-' || (c) == '_' || (c) == '.' || \
  (c) == '!' || (c) == '~' || (c) == '*' || (c) == '\'' || (c) == '(' || \
  (c) == ')')
#define CROW_IS_USERINFO_CHAR(c) (CROW_IS_ALPHANUM(c) || CROW_IS_MARK(c) || (c) == '%' || \
  (c) == ';' || (c) == ':' || (c) == '&' || (c) == '=' || (c) == '+' || \
  (c) == '$' || (c) == ',')

#if CROW_HTTP_PARSER_STRICT
#define CROW_TOKEN(c)            (tokens[(unsigned char)c])
#define CROW_IS_URL_CHAR(c)      (CROW_BIT_AT(normal_url_char, (unsigned char)c))
#define CROW_IS_HOST_CHAR(c)     (CROW_IS_ALPHANUM(c) || (c) == '.' || (c) == '-')
#else
#define CROW_TOKEN(c)            ((c == ' ') ? ' ' : tokens[(unsigned char)c])
#define CROW_IS_URL_CHAR(c)                                                         \
  (CROW_BIT_AT(normal_url_char, (unsigned char)c) || ((c) & 0x80))
#define CROW_IS_HOST_CHAR(c)                                                        \
  (CROW_IS_ALPHANUM(c) || (c) == '.' || (c) == '-' || (c) == '_')
#endif

#define CROW_start_state (parser->type == HTTP_REQUEST ? s_start_req : s_start_res)

#if CROW_HTTP_PARSER_STRICT
# define CROW_STRICT_CHECK(cond)                                          \
do {                                                                 \
  if (cond) {                                                        \
    CROW_SET_ERRNO(HPE_STRICT);                                           \
    goto error;                                                      \
  }                                                                  \
} while (0)
# define CROW_NEW_MESSAGE() (http_should_keep_alive(parser) ? CROW_start_state : s_dead)
#else
# define CROW_STRICT_CHECK(cond)
# define CROW_NEW_MESSAGE() CROW_start_state
#endif

    int http_message_needs_eof(const http_parser *parser);

    /* Our URL parser.
     *
     * This is designed to be shared by http_parser_execute() for URL validation,
     * hence it has a state transition + byte-for-byte interface. In addition, it
     * is meant to be embedded in http_parser_parse_url(), which does the dirty
     * work of turning state transitions URL components for its API.
     *
     * This function should only be invoked with non-space characters. It is
     * assumed that the caller cares about (and can detect) the transition between
     * URL and non-URL states by looking for these.
     */
    inline enum state
    parse_url_char(enum state s, const char ch)
    {
#if CROW_HTTP_PARSER_STRICT
# define CROW_T(v) 0
#else
# define CROW_T(v) v
#endif

    static const uint8_t normal_url_char[32] = {
        /*   0 nul    1 soh    2 stx    3 etx    4 eot    5 enq    6 ack    7 bel  */
        0 | 0 | 0 | 0 | 0 | 0 | 0 | 0,
        /*   8 bs     9 ht    10 nl    11 vt    12 np    13 cr    14 so    15 si   */
        0 | CROW_T(2) | 0 | 0 | CROW_T(16) | 0 | 0 | 0,
        /*  16 dle   17 dc1   18 dc2   19 dc3   20 dc4   21 nak   22 syn   23 etb */
        0 | 0 | 0 | 0 | 0 | 0 | 0 | 0,
        /*  24 can   25 em    26 sub   27 esc   28 fs    29 gs    30 rs    31 us  */
        0 | 0 | 0 | 0 | 0 | 0 | 0 | 0,
        /*  32 sp    33  !    34  "    35  #    36  $    37  %    38  &    39  '  */
        0 | 2 | 4 | 0 | 16 | 32 | 64 | 128,
        /*  40  (    41  )    42  *    43  +    44  ,    45  -    46  .    47  /  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /*  48  0    49  1    50  2    51  3    52  4    53  5    54  6    55  7  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /*  56  8    57  9    58  :    59  ;    60  <    61  =    62  >    63  ?  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 0,
        /*  64  @    65  A    66  B    67  C    68  D    69  E    70  F    71  G  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /*  72  H    73  I    74  J    75  K    76  L    77  M    78  N    79  O  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /*  80  P    81  Q    82  R    83  S    84  CROW_T    85  U    86  V    87  W  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /*  88  X    89  Y    90  Z    91  [    92  \    93  ]    94  ^    95  _  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /*  96  `    97  a    98  b    99  c   100  d   101  e   102  f   103  g  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /* 104  h   105  i   106  j   107  k   108  l   109  m   110  n   111  o  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /* 112  p   113  q   114  r   115  s   116  t   117  u   118  v   119  w  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /* 120  x   121  y   122  z   123  {   124  |   125  }   126  ~   127 del */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 0,};

#undef CROW_T

    if (ch == ' ' || ch == '\r' || ch == '\n') {
        return s_dead;
    }

#if CROW_HTTP_PARSER_STRICT
    if (ch == '\t' || ch == '\f') {
        return s_dead;
    }
#endif

    switch (s) {
        case s_req_spaces_before_url:
        /* Proxied requests are followed by scheme of an absolute URI (alpha).
         * All methods except CONNECT are followed by '/' or '*'.
         */

        if (ch == '/' || ch == '*') {
            return s_req_path;
        }

        if (CROW_IS_ALPHA(ch)) {
            return s_req_schema;
        }

        break;

        case s_req_schema:
        if (CROW_IS_ALPHA(ch)) {
            return s;
        }

        if (ch == ':') {
            return s_req_schema_slash;
        }

        break;

        case s_req_schema_slash:
        if (ch == '/') {
            return s_req_schema_slash_slash;
        }

        break;

        case s_req_schema_slash_slash:
        if (ch == '/') {
            return s_req_server_start;
        }

        break;

        case s_req_server_with_at:
        if (ch == '@') {
            return s_dead;
        }

        /* FALLTHROUGH */
        case s_req_server_start:
        case s_req_server:
        if (ch == '/') {
            return s_req_path;
        }

        if (ch == '?') {
            return s_req_query_string_start;
        }

        if (ch == '@') {
            return s_req_server_with_at;
        }

        if (CROW_IS_USERINFO_CHAR(ch) || ch == '[' || ch == ']') {
            return s_req_server;
        }

        break;

        case s_req_path:
        if (CROW_IS_URL_CHAR(ch)) {
            return s;
        }

        switch (ch) {
            case '?':
            return s_req_query_string_start;

            case '#':
            return s_req_fragment_start;
        }

        break;

        case s_req_query_string_start:
        case s_req_query_string:
        if (CROW_IS_URL_CHAR(ch)) {
            return s_req_query_string;
        }

        switch (ch) {
            case '?':
            /* allow extra '?' in query string */
            return s_req_query_string;

            case '#':
            return s_req_fragment_start;
        }

        break;

        case s_req_fragment_start:
        if (CROW_IS_URL_CHAR(ch)) {
            return s_req_fragment;
        }

        switch (ch) {
            case '?':
            return s_req_fragment;

            case '#':
            return s;
        }

        break;

        case s_req_fragment:
        if (CROW_IS_URL_CHAR(ch)) {
            return s;
        }

        switch (ch) {
            case '?':
            case '#':
            return s;
        }

        break;

        default:
        break;
    }

    /* We should never fall out of the switch above unless there's an error */
    return s_dead;
}

inline size_t http_parser_execute (http_parser *parser,
const http_parser_settings *settings,
const char *data,
size_t len)
{
    static const char *method_strings[] =
    {
#define CROW_XX(num, name, string) #string,
    CROW_HTTP_METHOD_MAP(CROW_XX)
#undef CROW_XX
};

/* Tokens as defined by rfc 2616. Also lowercases them.
 *        token       = 1*<any CHAR except CTLs or separators>
 *     separators     = "(" | ")" | "<" | ">" | "@"
 *                    | "," | ";" | ":" | "\" | <">
 *                    | "/" | "[" | "]" | "?" | "="
 *                    | "{" | "}" | SP | HT
 */
static const char tokens[256] = {
    /*   0 nul    1 soh    2 stx    3 etx    4 eot    5 enq    6 ack    7 bel  */
    0, 0, 0, 0, 0, 0, 0, 0,
    /*   8 bs     9 ht    10 nl    11 vt    12 np    13 cr    14 so    15 si   */
    0, 0, 0, 0, 0, 0, 0, 0,
    /*  16 dle   17 dc1   18 dc2   19 dc3   20 dc4   21 nak   22 syn   23 etb */
    0, 0, 0, 0, 0, 0, 0, 0,
    /*  24 can   25 em    26 sub   27 esc   28 fs    29 gs    30 rs    31 us  */
    0, 0, 0, 0, 0, 0, 0, 0,
    /*  32 sp    33  !    34  "    35  #    36  $    37  %    38  &    39  '  */
    0, '!', 0, '#', '$', '%', '&', '\'',
    /*  40  (    41  )    42  *    43  +    44  ,    45  -    46  .    47  /  */
    0, 0, '*', '+', 0, '-', '.', 0,
    /*  48  0    49  1    50  2    51  3    52  4    53  5    54  6    55  7  */
    '0', '1', '2', '3', '4', '5', '6', '7',
    /*  56  8    57  9    58  :    59  ;    60  <    61  =    62  >    63  ?  */
    '8', '9', 0, 0, 0, 0, 0, 0,
    /*  64  @    65  A    66  B    67  C    68  D    69  E    70  F    71  G  */
    0, 'a', 'b', 'c', 'd', 'e', 'f', 'g',
    /*  72  H    73  I    74  J    75  K    76  L    77  M    78  N    79  O  */
    'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',
    /*  80  P    81  Q    82  R    83  S    84  T    85  U    86  V    87  W  */
    'p', 'q', 'r', 's', 't', 'u', 'v', 'w',
    /*  88  X    89  Y    90  Z    91  [    92  \    93  ]    94  ^    95  _  */
    'x', 'y', 'z', 0, 0, 0, '^', '_',
    /*  96  `    97  a    98  b    99  c   100  d   101  e   102  f   103  g  */
    '`', 'a', 'b', 'c', 'd', 'e', 'f', 'g',
    /* 104  h   105  i   106  j   107  k   108  l   109  m   110  n   111  o  */
    'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',
    /* 112  p   113  q   114  r   115  s   116  t   117  u   118  v   119  w  */
    'p', 'q', 'r', 's', 't', 'u', 'v', 'w',
    /* 120  x   121  y   122  z   123  {   124  |   125  }   126  ~   127 del */
    'x', 'y', 'z', 0, '|', 0, '~', 0};

static const int8_t unhex[256] =
{   -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
    ,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
    ,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
    , 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,-1,-1,-1,-1,-1,-1
    ,-1,10,11,12,13,14,15,-1,-1,-1,-1,-1,-1,-1,-1,-1
    ,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
    ,-1,10,11,12,13,14,15,-1,-1,-1,-1,-1,-1,-1,-1,-1
    ,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
};

char c, ch;
int8_t unhex_val;
const char *p = data;
const char *header_field_mark = 0;
const char *header_value_mark = 0;
const char *url_mark = 0;
const char *body_mark = 0;
const char *status_mark = 0;

/* We're in an error state. Don't bother doing anything. */
if (CROW_HTTP_PARSER_ERRNO(parser) != HPE_OK) {
    return 0;
}

if (len == 0) {
    switch (parser->state) {
        case s_body_identity_eof:
        /* Use of CROW_CALLBACK_NOTIFY() here would erroneously return 1 byte read if
         * we got paused.
         */
        CROW_CALLBACK_NOTIFY_NOADVANCE(message_complete);
        return 0;

        case s_dead:
        case s_start_req_or_res:
        case s_start_res:
        case s_start_req:
        return 0;

        default:
        CROW_SET_ERRNO(HPE_INVALID_EOF_STATE);
        return 1;
    }
}

if (parser->state == s_header_field)
header_field_mark = data;
if (parser->state == s_header_value)
header_value_mark = data;
switch (parser->state) {
    case s_req_path:
    case s_req_schema:
    case s_req_schema_slash:
    case s_req_schema_slash_slash:
    case s_req_server_start:
    case s_req_server:
    case s_req_server_with_at:
    case s_req_query_string_start:
    case s_req_query_string:
    case s_req_fragment_start:
    case s_req_fragment:
    url_mark = data;
    break;
    case s_res_status:
    status_mark = data;
    break;
}

for (p=data; p != data + len; p++) {
    ch = *p;

    if (CROW_PARSING_HEADER(parser->state)) {
        ++parser->nread;
        /* Don't allow the total size of the HTTP headers (including the status
         * line) to exceed CROW_HTTP_MAX_HEADER_SIZE.  This check is here to protect
         * embedders against denial-of-service attacks where the attacker feeds
         * us a never-ending header that the embedder keeps buffering.
         *
         * This check is arguably the responsibility of embedders but we're doing
         * it on the embedder's behalf because most won't bother and this way we
         * make the web a little safer.  CROW_HTTP_MAX_HEADER_SIZE is still far bigger
         * than any reasonable request or response so this should never affect
         * day-to-day operation.
         */
        if (parser->nread > (CROW_HTTP_MAX_HEADER_SIZE)) {
            CROW_SET_ERRNO(HPE_HEADER_OVERFLOW);
            goto error;
        }
    }

    reexecute_byte:
    switch (parser->state) {

        case s_dead:
        /* this state is used after a 'Connection: close' message
         * the parser will error out if it reads another message
         */
        if (ch == CROW_CR || ch == CROW_LF)
        break;

        CROW_SET_ERRNO(HPE_CLOSED_CONNECTION);
        goto error;

        case s_start_req_or_res:
        {
            if (ch == CROW_CR || ch == CROW_LF)
            break;
            parser->flags = 0;
            parser->content_length = CROW_ULLONG_MAX;

            if (ch == 'H') {
                parser->state = s_res_or_resp_H;

                CROW_CALLBACK_NOTIFY(message_begin);
            }
            else {
                parser->type = HTTP_REQUEST;
                parser->state = s_start_req;
                goto reexecute_byte;
            }

            break;
        }

        case s_res_or_resp_H:
        if (ch == 'T') {
            parser->type = HTTP_RESPONSE;
            parser->state = s_res_HT;
        }
        else {
            if (ch != 'E') {
                CROW_SET_ERRNO(HPE_INVALID_CONSTANT);
                goto error;
            }

            parser->type = HTTP_REQUEST;
            parser->method = HTTP_HEAD;
            parser->index = 2;
            parser->state = s_req_method;
        }
        break;

        case s_start_res:
        {
            parser->flags = 0;
            parser->content_length = CROW_ULLONG_MAX;

            switch (ch) {
                case 'H':
                parser->state = s_res_H;
                break;

                case CROW_CR:
                case CROW_LF:
                break;

                default:
                CROW_SET_ERRNO(HPE_INVALID_CONSTANT);
                goto error;
            }

            CROW_CALLBACK_NOTIFY(message_begin);
            break;
        }

        case s_res_H:
        CROW_STRICT_CHECK(ch != 'T');
        parser->state = s_res_HT;
        break;

        case s_res_HT:
        CROW_STRICT_CHECK(ch != 'T');
        parser->state = s_res_HTT;
        break;

        case s_res_HTT:
        CROW_STRICT_CHECK(ch != 'P');
        parser->state = s_res_HTTP;
        break;

        case s_res_HTTP:
        CROW_STRICT_CHECK(ch != '/');
        parser->state = s_res_first_http_major;
        break;

        case s_res_first_http_major:
        if (ch < '0' || ch > '9') {
            CROW_SET_ERRNO(HPE_INVALID_VERSION);
            goto error;
        }

        parser->http_major = ch - '0';
        parser->state = s_res_http_major;
        break;

        /* major HTTP version or dot */
        case s_res_http_major:
        {
            if (ch == '.') {
                parser->state = s_res_first_http_minor;
                break;
            }

            if (!CROW_IS_NUM(ch)) {
                CROW_SET_ERRNO(HPE_INVALID_VERSION);
                goto error;
            }

            parser->http_major *= 10;
            parser->http_major += ch - '0';

            if (parser->http_major > 999) {
                CROW_SET_ERRNO(HPE_INVALID_VERSION);
                goto error;
            }

            break;
        }

        /* first digit of minor HTTP version */
        case s_res_first_http_minor:
        if (!CROW_IS_NUM(ch)) {
            CROW_SET_ERRNO(HPE_INVALID_VERSION);
            goto error;
        }

        parser->http_minor = ch - '0';
        parser->state = s_res_http_minor;
        break;

        /* minor HTTP version or end of request line */
        case s_res_http_minor:
        {
            if (ch == ' ') {
                parser->state = s_res_first_status_code;
                break;
            }

            if (!CROW_IS_NUM(ch)) {
                CROW_SET_ERRNO(HPE_INVALID_VERSION);
                goto error;
            }

            parser->http_minor *= 10;
            parser->http_minor += ch - '0';

            if (parser->http_minor > 999) {
                CROW_SET_ERRNO(HPE_INVALID_VERSION);
                goto error;
            }

            break;
        }

        case s_res_first_status_code:
        {
            if (!CROW_IS_NUM(ch)) {
                if (ch == ' ') {
                    break;
                }

                CROW_SET_ERRNO(HPE_INVALID_STATUS);
                goto error;
            }
            parser->status_code = ch - '0';
            parser->state = s_res_status_code;
            break;
        }

        case s_res_status_code:
        {
            if (!CROW_IS_NUM(ch)) {
                switch (ch) {
                    case ' ':
                    parser->state = s_res_status_start;
                    break;
                    case CROW_CR:
                    parser->state = s_res_line_almost_done;
                    break;
                    case CROW_LF:
                    parser->state = s_header_field_start;
                    break;
                    default:
                    CROW_SET_ERRNO(HPE_INVALID_STATUS);
                    goto error;
                }
                break;
            }

            parser->status_code *= 10;
            parser->status_code += ch - '0';

            if (parser->status_code > 999) {
                CROW_SET_ERRNO(HPE_INVALID_STATUS);
                goto error;
            }

            break;
        }

        case s_res_status_start:
        {
            if (ch == CROW_CR) {
                parser->state = s_res_line_almost_done;
                break;
            }

            if (ch == CROW_LF) {
                parser->state = s_header_field_start;
                break;
            }

            CROW_MARK(status);
            parser->state = s_res_status;
            parser->index = 0;
            break;
        }

        case s_res_status:
        if (ch == CROW_CR) {
            parser->state = s_res_line_almost_done;
            CROW_CALLBACK_DATA(status);
            break;
        }

        if (ch == CROW_LF) {
            parser->state = s_header_field_start;
            CROW_CALLBACK_DATA(status);
            break;
        }

        break;

        case s_res_line_almost_done:
        CROW_STRICT_CHECK(ch != CROW_LF);
        parser->state = s_header_field_start;
        break;

        case s_start_req:
        {
            if (ch == CROW_CR || ch == CROW_LF)
            break;
            parser->flags = 0;
            parser->content_length = CROW_ULLONG_MAX;

            if (!CROW_IS_ALPHA(ch)) {
                CROW_SET_ERRNO(HPE_INVALID_METHOD);
                goto error;
            }

            parser->method = (enum http_method) 0;
            parser->index = 1;
            switch (ch) {
                case 'C': parser->method = HTTP_CONNECT; /* or COPY, CHECKOUT */break;
                case 'D': parser->method = HTTP_DELETE; break;
                case 'G': parser->method = HTTP_GET; break;
                case 'H': parser->method = HTTP_HEAD; break;
                case 'L': parser->method = HTTP_LOCK; break;
                case 'M': parser->method = HTTP_MKCOL; /* or MOVE, MKACTIVITY, MERGE, M-SEARCH, MKCALENDAR */break;
                case 'N': parser->method = HTTP_NOTIFY; break;
                case 'O': parser->method = HTTP_OPTIONS; break;
                case 'P': parser->method = HTTP_POST;
                /* or PROPFIND|PROPPATCH|PUT|PATCH|PURGE */
                break;
                case 'R': parser->method = HTTP_REPORT; break;
                case 'S': parser->method = HTTP_SUBSCRIBE; /* or SEARCH */break;
                case 'T': parser->method = HTTP_TRACE; break;
                case 'U': parser->method = HTTP_UNLOCK; /* or UNSUBSCRIBE */break;
                default:
                CROW_SET_ERRNO(HPE_INVALID_METHOD);
                goto error;
            }
            parser->state = s_req_method;

            CROW_CALLBACK_NOTIFY(message_begin);

            break;
        }

        case s_req_method:
        {
            const char *matcher;
            if (ch == '\0') {
                CROW_SET_ERRNO(HPE_INVALID_METHOD);
                goto error;
            }

            matcher = method_strings[parser->method];
            if (ch == ' ' && matcher[parser->index] == '\0') {
                parser->state = s_req_spaces_before_url;
            }
            else if (ch == matcher[parser->index]) {
                ; /* nada */
            }
            else if (parser->method == HTTP_CONNECT) {
                if (parser->index == 1 && ch == 'H') {
                    parser->method = HTTP_CHECKOUT;
                }
                else if (parser->index == 2 && ch == 'P') {
                    parser->method = HTTP_COPY;
                }
                else {
                    CROW_SET_ERRNO(HPE_INVALID_METHOD);
                    goto error;
                }
            }
            else if (parser->method == HTTP_MKCOL) {
                if (parser->index == 1 && ch == 'O') {
                    parser->method = HTTP_MOVE;
                }
                else if (parser->index == 1 && ch == 'E') {
                    parser->method = HTTP_MERGE;
                }
                else if (parser->index == 1 && ch == '-') {
                    parser->method = HTTP_MSEARCH;
                }
                else if (parser->index == 2 && ch == 'A') {
                    parser->method = HTTP_MKACTIVITY;
                }
                else if (parser->index == 3 && ch == 'A') {
                    parser->method = HTTP_MKCALENDAR;
                }
                else {
                    CROW_SET_ERRNO(HPE_INVALID_METHOD);
                    goto error;
                }
            }
            else if (parser->method == HTTP_SUBSCRIBE) {
                if (parser->index == 1 && ch == 'E') {
                    parser->method = HTTP_SEARCH;
                }
                else {
                    CROW_SET_ERRNO(HPE_INVALID_METHOD);
                    goto error;
                }
            }
            else if (parser->index == 1 && parser->method == HTTP_POST) {
                if (ch == 'R') {
                    parser->method = HTTP_PROPFIND; /* or HTTP_PROPPATCH */
                }
                else if (ch == 'U') {
                    parser->method = HTTP_PUT; /* or HTTP_PURGE */
                }
                else if (ch == 'A') {
                    parser->method = HTTP_PATCH;
                }
                else {
                    CROW_SET_ERRNO(HPE_INVALID_METHOD);
                    goto error;
                }
            }
            else if (parser->index == 2) {
                if (parser->method == HTTP_PUT) {
                    if (ch == 'R') {
                        parser->method = HTTP_PURGE;
                    }
                    else {
                        CROW_SET_ERRNO(HPE_INVALID_METHOD);
                        goto error;
                    }
                }
                else if (parser->method == HTTP_UNLOCK) {
                    if (ch == 'S') {
                        parser->method = HTTP_UNSUBSCRIBE;
                    }
                    else {
                        CROW_SET_ERRNO(HPE_INVALID_METHOD);
                        goto error;
                    }
                }
                else {
                    CROW_SET_ERRNO(HPE_INVALID_METHOD);
                    goto error;
                }
            }
            else if (parser->index == 4 && parser->method == HTTP_PROPFIND && ch == 'P') {
                parser->method = HTTP_PROPPATCH;
            }
            else {
                CROW_SET_ERRNO(HPE_INVALID_METHOD);
                goto error;
            }

            ++parser->index;
            break;
        }

        case s_req_spaces_before_url:
        {
            if (ch == ' ') break;

            CROW_MARK(url);
            if (parser->method == HTTP_CONNECT) {
                parser->state = s_req_server_start;
            }

            parser->state = parse_url_char((enum state)parser->state, ch);
            if (parser->state == s_dead) {
                CROW_SET_ERRNO(HPE_INVALID_URL);
                goto error;
            }

            break;
        }

        case s_req_schema:
        case s_req_schema_slash:
        case s_req_schema_slash_slash:
        case s_req_server_start:
        {
            switch (ch) {
                /* No whitespace allowed here */
                case ' ':
                case CROW_CR:
                case CROW_LF:
                CROW_SET_ERRNO(HPE_INVALID_URL);
                goto error;
                default:
                parser->state = parse_url_char((enum state)parser->state, ch);
                if (parser->state == s_dead) {
                    CROW_SET_ERRNO(HPE_INVALID_URL);
                    goto error;
                }
            }

            break;
        }

        case s_req_server:
        case s_req_server_with_at:
        case s_req_path:
        case s_req_query_string_start:
        case s_req_query_string:
        case s_req_fragment_start:
        case s_req_fragment:
        {
            switch (ch) {
                case ' ':
                parser->state = s_req_http_start;
                CROW_CALLBACK_DATA(url);
                break;
                case CROW_CR:
                case CROW_LF:
                parser->http_major = 0;
                parser->http_minor = 9;
                parser->state = (ch == CROW_CR) ?
                s_req_line_almost_done :
                s_header_field_start;
                CROW_CALLBACK_DATA(url);
                break;
                default:
                parser->state = parse_url_char((enum state)parser->state, ch);
                if (parser->state == s_dead) {
                    CROW_SET_ERRNO(HPE_INVALID_URL);
                    goto error;
                }
            }
            break;
        }

        case s_req_http_start:
        switch (ch) {
            case 'H':
            parser->state = s_req_http_H;
            break;
            case ' ':
            break;
            default:
            CROW_SET_ERRNO(HPE_INVALID_CONSTANT);
            goto error;
        }
        break;

        case s_req_http_H:
        CROW_STRICT_CHECK(ch != 'T');
        parser->state = s_req_http_HT;
        break;

        case s_req_http_HT:
        CROW_STRICT_CHECK(ch != 'T');
        parser->state = s_req_http_HTT;
        break;

        case s_req_http_HTT:
        CROW_STRICT_CHECK(ch != 'P');
        parser->state = s_req_http_HTTP;
        break;

        case s_req_http_HTTP:
        CROW_STRICT_CHECK(ch != '/');
        parser->state = s_req_first_http_major;
        break;

        /* first digit of major HTTP version */
        case s_req_first_http_major:
        if (ch < '1' || ch > '9') {
            CROW_SET_ERRNO(HPE_INVALID_VERSION);
            goto error;
        }

        parser->http_major = ch - '0';
        parser->state = s_req_http_major;
        break;

        /* major HTTP version or dot */
        case s_req_http_major:
        {
            if (ch == '.') {
                parser->state = s_req_first_http_minor;
                break;
            }

            if (!CROW_IS_NUM(ch)) {
                CROW_SET_ERRNO(HPE_INVALID_VERSION);
                goto error;
            }

            parser->http_major *= 10;
            parser->http_major += ch - '0';

            if (parser->http_major > 999) {
                CROW_SET_ERRNO(HPE_INVALID_VERSION);
                goto error;
            }

            break;
        }

        /* first digit of minor HTTP version */
        case s_req_first_http_minor:
        if (!CROW_IS_NUM(ch)) {
            CROW_SET_ERRNO(HPE_INVALID_VERSION);
            goto error;
        }

        parser->http_minor = ch - '0';
        parser->state = s_req_http_minor;
        break;

        /* minor HTTP version or end of request line */
        case s_req_http_minor:
        {
            if (ch == CROW_CR) {
                parser->state = s_req_line_almost_done;
                break;
            }

            if (ch == CROW_LF) {
                parser->state = s_header_field_start;
                break;
            }

            /* XXX allow spaces after digit? */

            if (!CROW_IS_NUM(ch)) {
                CROW_SET_ERRNO(HPE_INVALID_VERSION);
                goto error;
            }

            parser->http_minor *= 10;
            parser->http_minor += ch - '0';

            if (parser->http_minor > 999) {
                CROW_SET_ERRNO(HPE_INVALID_VERSION);
                goto error;
            }

            break;
        }

        /* end of request line */
        case s_req_line_almost_done:
        {
            if (ch != CROW_LF) {
                CROW_SET_ERRNO(HPE_LF_EXPECTED);
                goto error;
            }

            parser->state = s_header_field_start;
            break;
        }

        case s_header_field_start:
        {
            if (ch == CROW_CR) {
                parser->state = s_headers_almost_done;
                break;
            }

            if (ch == CROW_LF) {
                /* they might be just sending \n instead of \r\n so this would be
                 * the second \n to denote the end of headers*/
                parser->state = s_headers_almost_done;
                goto reexecute_byte;
            }

            c = CROW_TOKEN(ch);

            if (!c) {
                CROW_SET_ERRNO(HPE_INVALID_HEADER_TOKEN);
                goto error;
            }

            CROW_MARK(header_field);

            parser->index = 0;
            parser->state = s_header_field;

            switch (c) {
                case 'c':
                parser->header_state = h_C;
                break;

                case 'p':
                parser->header_state = h_matching_proxy_connection;
                break;

                case 't':
                parser->header_state = h_matching_transfer_encoding;
                break;

                case 'u':
                parser->header_state = h_matching_upgrade;
                break;

                default:
                parser->header_state = h_general;
                break;
            }
            break;
        }

        case s_header_field:
        {
            c = CROW_TOKEN(ch);

            if (c) {
                switch (parser->header_state) {
                    case h_general:
                    break;

                    case h_C:
                    parser->index++;
                    parser->header_state = (c == 'o' ? h_CO : h_general);
                    break;

                    case h_CO:
                    parser->index++;
                    parser->header_state = (c == 'n' ? h_CON : h_general);
                    break;

                    case h_CON:
                    parser->index++;
                    switch (c) {
                        case 'n':
                        parser->header_state = h_matching_connection;
                        break;
                        case 't':
                        parser->header_state = h_matching_content_length;
                        break;
                        default:
                        parser->header_state = h_general;
                        break;
                    }
                    break;

                    /* connection */

                    case h_matching_connection:
                    parser->index++;
                    if (parser->index > sizeof(CROW_CONNECTION)-1
                    || c != CROW_CONNECTION[parser->index]) {
                        parser->header_state = h_general;
                    }
                    else if (parser->index == sizeof(CROW_CONNECTION)-2) {
                        parser->header_state = h_connection;
                    }
                    break;

                    /* proxy-connection */

                    case h_matching_proxy_connection:
                    parser->index++;
                    if (parser->index > sizeof(CROW_PROXY_CONNECTION)-1
                    || c != CROW_PROXY_CONNECTION[parser->index]) {
                        parser->header_state = h_general;
                    }
                    else if (parser->index == sizeof(CROW_PROXY_CONNECTION)-2) {
                        parser->header_state = h_connection;
                    }
                    break;

                    /* content-length */

                    case h_matching_content_length:
                    parser->index++;
                    if (parser->index > sizeof(CROW_CONTENT_LENGTH)-1
                    || c != CROW_CONTENT_LENGTH[parser->index]) {
                        parser->header_state = h_general;
                    }
                    else if (parser->index == sizeof(CROW_CONTENT_LENGTH)-2) {
                        parser->header_state = h_content_length;
                    }
                    break;

                    /* transfer-encoding */

                    case h_matching_transfer_encoding:
                    parser->index++;
                    if (parser->index > sizeof(CROW_TRANSFER_ENCODING)-1
                    || c != CROW_TRANSFER_ENCODING[parser->index]) {
                        parser->header_state = h_general;
                    }
                    else if (parser->index == sizeof(CROW_TRANSFER_ENCODING)-2) {
                        parser->header_state = h_transfer_encoding;
                    }
                    break;

                    /* upgrade */

                    case h_matching_upgrade:
                    parser->index++;
                    if (parser->index > sizeof(CROW_UPGRADE)-1
                    || c != CROW_UPGRADE[parser->index]) {
                        parser->header_state = h_general;
                    }
                    else if (parser->index == sizeof(CROW_UPGRADE)-2) {
                        parser->header_state = h_upgrade;
                    }
                    break;

                    case h_connection:
                    case h_content_length:
                    case h_transfer_encoding:
                    case h_upgrade:
                    if (ch != ' ') parser->header_state = h_general;
                    break;

                    default:
                    assert(0 && "Unknown header_state");
                    break;
                }
                break;
            }

            if (ch == ':') {
                parser->state = s_header_value_discard_ws;
                CROW_CALLBACK_DATA(header_field);
                break;
            }

            if (ch == CROW_CR) {
                parser->state = s_header_almost_done;
                CROW_CALLBACK_DATA(header_field);
                break;
            }

            if (ch == CROW_LF) {
                parser->state = s_header_field_start;
                CROW_CALLBACK_DATA(header_field);
                break;
            }

            CROW_SET_ERRNO(HPE_INVALID_HEADER_TOKEN);
            goto error;
        }

        case s_header_value_discard_ws:
        if (ch == ' ' || ch == '\t') break;

        if (ch == CROW_CR) {
            parser->state = s_header_value_discard_ws_almost_done;
            break;
        }

        if (ch == CROW_LF) {
            parser->state = s_header_value_discard_lws;
            break;
        }

        /* FALLTHROUGH */

        case s_header_value_start:
        {
            CROW_MARK(header_value);

            parser->state = s_header_value;
            parser->index = 0;

            c = CROW_LOWER(ch);

            switch (parser->header_state) {
                case h_upgrade:
                parser->flags |= F_UPGRADE;
                parser->header_state = h_general;
                break;

                case h_transfer_encoding:
                /* looking for 'Transfer-Encoding: chunked' */
                if ('c' == c) {
                    parser->header_state = h_matching_transfer_encoding_chunked;
                }
                else {
                    parser->header_state = h_general;
                }
                break;

                case h_content_length:
                if (!CROW_IS_NUM(ch)) {
                    CROW_SET_ERRNO(HPE_INVALID_CONTENT_LENGTH);
                    goto error;
                }

                parser->content_length = ch - '0';
                break;

                case h_connection:
                /* looking for 'Connection: keep-alive' */
                if (c == 'k') {
                    parser->header_state = h_matching_connection_keep_alive;
                    /* looking for 'Connection: close' */
                }
                else if (c == 'c') {
                    parser->header_state = h_matching_connection_close;
                }
                else {
                    parser->header_state = h_general;
                }
                break;

                default:
                parser->header_state = h_general;
                break;
            }
            break;
        }

        case s_header_value:
        {

            if (ch == CROW_CR) {
                parser->state = s_header_almost_done;
                CROW_CALLBACK_DATA(header_value);
                break;
            }

            if (ch == CROW_LF) {
                parser->state = s_header_almost_done;
                CROW_CALLBACK_DATA_NOADVANCE(header_value);
                goto reexecute_byte;
            }

            c = CROW_LOWER(ch);

            switch (parser->header_state) {
                case h_general:
                break;

                case h_connection:
                case h_transfer_encoding:
                assert(0 && "Shouldn't get here.");
                break;

                case h_content_length:
                {
                    uint64_t t;

                    if (ch == ' ') break;

                    if (!CROW_IS_NUM(ch)) {
                        CROW_SET_ERRNO(HPE_INVALID_CONTENT_LENGTH);
                        goto error;
                    }

                    t = parser->content_length;
                    t *= 10;
                    t += ch - '0';

                    /* Overflow? Test against a conservative limit for simplicity. */
                    if ((CROW_ULLONG_MAX - 10) / 10 < parser->content_length) {
                        CROW_SET_ERRNO(HPE_INVALID_CONTENT_LENGTH);
                        goto error;
                    }

                    parser->content_length = t;
                    break;
                }

                /* Transfer-Encoding: chunked */
                case h_matching_transfer_encoding_chunked:
                parser->index++;
                if (parser->index > sizeof(CROW_CHUNKED)-1
                || c != CROW_CHUNKED[parser->index]) {
                    parser->header_state = h_general;
                }
                else if (parser->index == sizeof(CROW_CHUNKED)-2) {
                    parser->header_state = h_transfer_encoding_chunked;
                }
                break;

                /* looking for 'Connection: keep-alive' */
                case h_matching_connection_keep_alive:
                parser->index++;
                if (parser->index > sizeof(CROW_KEEP_ALIVE)-1
                || c != CROW_KEEP_ALIVE[parser->index]) {
                    parser->header_state = h_general;
                }
                else if (parser->index == sizeof(CROW_KEEP_ALIVE)-2) {
                    parser->header_state = h_connection_keep_alive;
                }
                break;

                /* looking for 'Connection: close' */
                case h_matching_connection_close:
                parser->index++;
                if (parser->index > sizeof(CROW_CLOSE)-1 || c != CROW_CLOSE[parser->index]) {
                    parser->header_state = h_general;
                }
                else if (parser->index == sizeof(CROW_CLOSE)-2) {
                    parser->header_state = h_connection_close;
                }
                break;

                case h_transfer_encoding_chunked:
                case h_connection_keep_alive:
                case h_connection_close:
                if (ch != ' ') parser->header_state = h_general;
                break;

                default:
                parser->state = s_header_value;
                parser->header_state = h_general;
                break;
            }
            break;
        }

        case s_header_almost_done:
        {
            CROW_STRICT_CHECK(ch != CROW_LF);

            parser->state = s_header_value_lws;
            break;
        }

        case s_header_value_lws:
        {
            if (ch == ' ' || ch == '\t') {
                parser->state = s_header_value_start;
                goto reexecute_byte;
            }

            /* finished the header */
            switch (parser->header_state) {
                case h_connection_keep_alive:
                parser->flags |= F_CONNECTION_KEEP_ALIVE;
                break;
                case h_connection_close:
                parser->flags |= F_CONNECTION_CLOSE;
                break;
                case h_transfer_encoding_chunked:
                parser->flags |= F_CHUNKED;
                break;
                default:
                break;
            }

            parser->state = s_header_field_start;
            goto reexecute_byte;
        }

        case s_header_value_discard_ws_almost_done:
        {
            CROW_STRICT_CHECK(ch != CROW_LF);
            parser->state = s_header_value_discard_lws;
            break;
        }

        case s_header_value_discard_lws:
        {
            if (ch == ' ' || ch == '\t') {
                parser->state = s_header_value_discard_ws;
                break;
            }
            else {
                /* header value was empty */
                CROW_MARK(header_value);
                parser->state = s_header_field_start;
                CROW_CALLBACK_DATA_NOADVANCE(header_value);
                goto reexecute_byte;
            }
        }

        case s_headers_almost_done:
        {
            CROW_STRICT_CHECK(ch != CROW_LF);

            if (parser->flags & F_TRAILING) {
                /* End of a chunked request */
                parser->state = CROW_NEW_MESSAGE();
                CROW_CALLBACK_NOTIFY(message_complete);
                break;
            }

            parser->state = s_headers_done;

            /* Set this here so that on_headers_complete() callbacks can see it */
            parser->upgrade =
            (parser->flags & F_UPGRADE || parser->method == HTTP_CONNECT);

            /* Here we call the headers_complete callback. This is somewhat
             * different than other callbacks because if the user returns 1, we
             * will interpret that as saying that this message has no body. This
             * is needed for the annoying case of recieving a response to a HEAD
             * request.
             *
             * We'd like to use CROW_CALLBACK_NOTIFY_NOADVANCE() here but we cannot, so
             * we have to simulate it by handling a change in errno below.
             */
            if (settings->on_headers_complete) {
                switch (settings->on_headers_complete(parser)) {
                    case 0:
                    break;

                    case 1:
                    parser->flags |= F_SKIPBODY;
                    break;

                    default:
                    CROW_SET_ERRNO(HPE_CB_headers_complete);
                    return p - data; /* Error */
                }
            }

            if (CROW_HTTP_PARSER_ERRNO(parser) != HPE_OK) {
                return p - data;
            }

            goto reexecute_byte;
        }

        case s_headers_done:
        {
            CROW_STRICT_CHECK(ch != CROW_LF);

            parser->nread = 0;

            /* Exit, the rest of the connect is in a different protocol. */
            if (parser->upgrade) {
                parser->state = CROW_NEW_MESSAGE();
                CROW_CALLBACK_NOTIFY(message_complete);
                return (p - data) + 1;
            }

            if (parser->flags & F_SKIPBODY) {
                parser->state = CROW_NEW_MESSAGE();
                CROW_CALLBACK_NOTIFY(message_complete);
            }
            else if (parser->flags & F_CHUNKED) {
                /* chunked encoding - ignore Content-Length header */
                parser->state = s_chunk_size_start;
            }
            else {
                if (parser->content_length == 0) {
                    /* Content-Length header given but zero: Content-Length: 0\r\n */
                    parser->state = CROW_NEW_MESSAGE();
                    CROW_CALLBACK_NOTIFY(message_complete);
                }
                else if (parser->content_length != CROW_ULLONG_MAX) {
                    /* Content-Length header given and non-zero */
                    parser->state = s_body_identity;
                }
                else {
                    if (parser->type == HTTP_REQUEST ||
                    !http_message_needs_eof(parser)) {
                        /* Assume content-length 0 - read the next */
                        parser->state = CROW_NEW_MESSAGE();
                        CROW_CALLBACK_NOTIFY(message_complete);
                    }
                    else {
                        /* Read body until EOF */
                        parser->state = s_body_identity_eof;
                    }
                }
            }

            break;
        }

        case s_body_identity:
        {
            uint64_t to_read = CROW_MIN(parser->content_length,
            (uint64_t) ((data + len) - p));

            assert(parser->content_length != 0
            && parser->content_length != CROW_ULLONG_MAX);

            /* The difference between advancing content_length and p is because
             * the latter will automaticaly advance on the next loop iteration.
             * Further, if content_length ends up at 0, we want to see the last
             * byte again for our message complete callback.
             */
            CROW_MARK(body);
            parser->content_length -= to_read;
            p += to_read - 1;

            if (parser->content_length == 0) {
                parser->state = s_message_done;

                /* Mimic CROW_CALLBACK_DATA_NOADVANCE() but with one extra byte.
                 *
                 * The alternative to doing this is to wait for the next byte to
                 * trigger the data callback, just as in every other case. The
                 * problem with this is that this makes it difficult for the test
                 * harness to distinguish between complete-on-EOF and
                 * complete-on-length. It's not clear that this distinction is
                 * important for applications, but let's keep it for now.
                 */
                CROW_CALLBACK_DATA_(body, p - body_mark + 1, p - data);
                goto reexecute_byte;
            }

            break;
        }

        /* read until EOF */
        case s_body_identity_eof:
        CROW_MARK(body);
        p = data + len - 1;

        break;

        case s_message_done:
        parser->state = CROW_NEW_MESSAGE();
        CROW_CALLBACK_NOTIFY(message_complete);
        break;

        case s_chunk_size_start:
        {
            assert(parser->nread == 1);
            assert(parser->flags & F_CHUNKED);

            unhex_val = unhex[(unsigned char)ch];
            if (unhex_val == -1) {
                CROW_SET_ERRNO(HPE_INVALID_CHUNK_SIZE);
                goto error;
            }

            parser->content_length = unhex_val;
            parser->state = s_chunk_size;
            break;
        }

        case s_chunk_size:
        {
            uint64_t t;

            assert(parser->flags & F_CHUNKED);

            if (ch == CROW_CR) {
                parser->state = s_chunk_size_almost_done;
                break;
            }

            unhex_val = unhex[(unsigned char)ch];

            if (unhex_val == -1) {
                if (ch == ';' || ch == ' ') {
                    parser->state = s_chunk_parameters;
                    break;
                }

                CROW_SET_ERRNO(HPE_INVALID_CHUNK_SIZE);
                goto error;
            }

            t = parser->content_length;
            t *= 16;
            t += unhex_val;

            /* Overflow? Test against a conservative limit for simplicity. */
            if ((CROW_ULLONG_MAX - 16) / 16 < parser->content_length) {
                CROW_SET_ERRNO(HPE_INVALID_CONTENT_LENGTH);
                goto error;
            }

            parser->content_length = t;
            break;
        }

        case s_chunk_parameters:
        {
            assert(parser->flags & F_CHUNKED);
            /* just ignore this shit. TODO check for overflow */
            if (ch == CROW_CR) {
                parser->state = s_chunk_size_almost_done;
                break;
            }
            break;
        }

        case s_chunk_size_almost_done:
        {
            assert(parser->flags & F_CHUNKED);
            CROW_STRICT_CHECK(ch != CROW_LF);

            parser->nread = 0;

            if (parser->content_length == 0) {
                parser->flags |= F_TRAILING;
                parser->state = s_header_field_start;
            }
            else {
                parser->state = s_chunk_data;
            }
            break;
        }

        case s_chunk_data:
        {
            uint64_t to_read = CROW_MIN(parser->content_length,
            (uint64_t) ((data + len) - p));

            assert(parser->flags & F_CHUNKED);
            assert(parser->content_length != 0
            && parser->content_length != CROW_ULLONG_MAX);

            /* See the explanation in s_body_identity for why the content
             * length and data pointers are managed this way.
             */
            CROW_MARK(body);
            parser->content_length -= to_read;
            p += to_read - 1;

            if (parser->content_length == 0) {
                parser->state = s_chunk_data_almost_done;
            }

            break;
        }

        case s_chunk_data_almost_done:
        assert(parser->flags & F_CHUNKED);
        assert(parser->content_length == 0);
        CROW_STRICT_CHECK(ch != CROW_CR);
        parser->state = s_chunk_data_done;
        CROW_CALLBACK_DATA(body);
        break;

        case s_chunk_data_done:
        assert(parser->flags & F_CHUNKED);
        CROW_STRICT_CHECK(ch != CROW_LF);
        parser->nread = 0;
        parser->state = s_chunk_size_start;
        break;

        default:
        assert(0 && "unhandled state");
        CROW_SET_ERRNO(HPE_INVALID_INTERNAL_STATE);
        goto error;
    }
}

/* Run callbacks for any marks that we have leftover after we ran our of
 * bytes. There should be at most one of these set, so it's OK to invoke
 * them in series (unset marks will not result in callbacks).
 *
 * We use the NOADVANCE() variety of callbacks here because 'p' has already
 * overflowed 'data' and this allows us to correct for the off-by-one that
 * we'd otherwise have (since CROW_CALLBACK_DATA() is meant to be run with a 'p'
 * value that's in-bounds).
 */

assert(((header_field_mark ? 1 : 0) +
(header_value_mark ? 1 : 0) +
(url_mark ? 1 : 0) +
(body_mark ? 1 : 0) +
(status_mark ? 1 : 0)) <= 1);

CROW_CALLBACK_DATA_NOADVANCE(header_field);
CROW_CALLBACK_DATA_NOADVANCE(header_value);
CROW_CALLBACK_DATA_NOADVANCE(url);
CROW_CALLBACK_DATA_NOADVANCE(body);
CROW_CALLBACK_DATA_NOADVANCE(status);

return len;

error:
if (CROW_HTTP_PARSER_ERRNO(parser) == HPE_OK) {
    CROW_SET_ERRNO(HPE_UNKNOWN);
}

return (p - data);
}

/* Does the parser need to see an EOF to find the end of the message? */
inline int
http_message_needs_eof (const http_parser *parser)
{
if (parser->type == HTTP_REQUEST) {
    return 0;
}

/* See RFC 2616 section 4.4 */
if (parser->status_code / 100 == 1 || /* 1xx e.g. Continue */
parser->status_code == 204 || /* No Content */
parser->status_code == 304 || /* Not Modified */
parser->flags & F_SKIPBODY) { /* response to a HEAD request */
    return 0;
}

if ((parser->flags & F_CHUNKED) || parser->content_length != CROW_ULLONG_MAX) {
    return 0;
}

return 1;
}

inline int
http_should_keep_alive (const http_parser *parser)
{
if (parser->http_major > 0 && parser->http_minor > 0) {
    /* HTTP/1.1 */
    if (parser->flags & F_CONNECTION_CLOSE) {
        return 0;
    }
}
else {
    /* HTTP/1.0 or earlier */
    if (!(parser->flags & F_CONNECTION_KEEP_ALIVE)) {
        return 0;
    }
}

return !http_message_needs_eof(parser);
}

inline const char *
http_method_str (enum http_method m)
{
static const char *method_strings[] =
{
#define CROW_XX(num, name, string) #string,
    CROW_HTTP_METHOD_MAP(CROW_XX)
#undef CROW_XX
};
return CROW_ELEM_AT(method_strings, m, "<unknown>");
}

inline void
http_parser_init (http_parser *parser, enum http_parser_type t)
{
void *data = parser->data; /* preserve application data */
memset(parser, 0, sizeof(*parser));
parser->data = data;
parser->type = t;
parser->state = (t == HTTP_REQUEST ? s_start_req : (t == HTTP_RESPONSE ? s_start_res : s_start_req_or_res));
parser->http_errno = HPE_OK;
}

inline const char *
http_errno_name(enum http_errno err) {
/* Map errno values to strings for human-readable output */
#define CROW_HTTP_STRERROR_GEN(n, s) { "HPE_" #n, s },
    static struct {
        const char *name;
        const char *description;
    }http_strerror_tab[] = {
        CROW_HTTP_ERRNO_MAP(CROW_HTTP_STRERROR_GEN)
    };
#undef CROW_HTTP_STRERROR_GEN
    assert(err < (sizeof(http_strerror_tab)/sizeof(http_strerror_tab[0])));
    return http_strerror_tab[err].name;
}

inline const char *
http_errno_description(enum http_errno err) {
    /* Map errno values to strings for human-readable output */
#define CROW_HTTP_STRERROR_GEN(n, s) { "HPE_" #n, s },
    static struct {
        const char *name;
        const char *description;
    }http_strerror_tab[] = {
        CROW_HTTP_ERRNO_MAP(CROW_HTTP_STRERROR_GEN)
    };
#undef CROW_HTTP_STRERROR_GEN
    assert(err < (sizeof(http_strerror_tab)/sizeof(http_strerror_tab[0])));
    return http_strerror_tab[err].description;
}

inline static enum http_host_state
http_parse_host_char(enum http_host_state s, const char ch) {
    switch(s) {
        case s_http_userinfo:
        case s_http_userinfo_start:
        if (ch == '@') {
            return s_http_host_start;
        }

        if (CROW_IS_USERINFO_CHAR(ch)) {
            return s_http_userinfo;
        }
        break;

        case s_http_host_start:
        if (ch == '[') {
            return s_http_host_v6_start;
        }

        if (CROW_IS_HOST_CHAR(ch)) {
            return s_http_host;
        }

        break;

        case s_http_host:
        if (CROW_IS_HOST_CHAR(ch)) {
            return s_http_host;
        }

        /* FALLTHROUGH */
        case s_http_host_v6_end:
        if (ch == ':') {
            return s_http_host_port_start;
        }

        break;

        case s_http_host_v6:
        if (ch == ']') {
            return s_http_host_v6_end;
        }

        /* FALLTHROUGH */
        case s_http_host_v6_start:
        if (CROW_IS_HEX(ch) || ch == ':' || ch == '.') {
            return s_http_host_v6;
        }

        break;

        case s_http_host_port:
        case s_http_host_port_start:
        if (CROW_IS_NUM(ch)) {
            return s_http_host_port;
        }

        break;

        default:
        break;
    }
    return s_http_host_dead;
}

inline int
http_parse_host(const char * buf, struct http_parser_url *u, int found_at) {
    enum http_host_state s;

    const char *p;
    size_t buflen = u->field_data[UF_HOST].off + u->field_data[UF_HOST].len;

    u->field_data[UF_HOST].len = 0;

    s = found_at ? s_http_userinfo_start : s_http_host_start;

    for (p = buf + u->field_data[UF_HOST].off; p < buf + buflen; p++) {
        enum http_host_state new_s = http_parse_host_char(s, *p);

        if (new_s == s_http_host_dead) {
            return 1;
        }

        switch(new_s) {
            case s_http_host:
            if (s != s_http_host) {
                u->field_data[UF_HOST].off = p - buf;
            }
            u->field_data[UF_HOST].len++;
            break;

            case s_http_host_v6:
            if (s != s_http_host_v6) {
                u->field_data[UF_HOST].off = p - buf;
            }
            u->field_data[UF_HOST].len++;
            break;

            case s_http_host_port:
            if (s != s_http_host_port) {
                u->field_data[UF_PORT].off = p - buf;
                u->field_data[UF_PORT].len = 0;
                u->field_set |= (1 << UF_PORT);
            }
            u->field_data[UF_PORT].len++;
            break;

            case s_http_userinfo:
            if (s != s_http_userinfo) {
                u->field_data[UF_USERINFO].off = p - buf;
                u->field_data[UF_USERINFO].len = 0;
                u->field_set |= (1 << UF_USERINFO);
            }
            u->field_data[UF_USERINFO].len++;
            break;

            default:
            break;
        }
        s = new_s;
    }

    /* Make sure we don't end somewhere unexpected */
    switch (s) {
        case s_http_host_start:
        case s_http_host_v6_start:
        case s_http_host_v6:
        case s_http_host_port_start:
        case s_http_userinfo:
        case s_http_userinfo_start:
        return 1;
        default:
        break;
    }

    return 0;
}

inline int
http_parser_parse_url(const char *buf, size_t buflen, int is_connect,
struct http_parser_url *u)
{
    enum state s;
    const char *p;
    enum http_parser_url_fields uf, old_uf;
    int found_at = 0;

    u->port = u->field_set = 0;
    s = is_connect ? s_req_server_start : s_req_spaces_before_url;
    old_uf = UF_MAX;

    for (p = buf; p < buf + buflen; p++) {
        s = parse_url_char(s, *p);

        /* Figure out the next field that we're operating on */
        switch (s) {
            case s_dead:
            return 1;

            /* Skip delimeters */
            case s_req_schema_slash:
            case s_req_schema_slash_slash:
            case s_req_server_start:
            case s_req_query_string_start:
            case s_req_fragment_start:
            continue;

            case s_req_schema:
            uf = UF_SCHEMA;
            break;

            case s_req_server_with_at:
            found_at = 1;

            /* FALLTROUGH */
            case s_req_server:
            uf = UF_HOST;
            break;

            case s_req_path:
            uf = UF_PATH;
            break;

            case s_req_query_string:
            uf = UF_QUERY;
            break;

            case s_req_fragment:
            uf = UF_FRAGMENT;
            break;

            default:
            assert(!"Unexpected state");
            return 1;
        }

        /* Nothing's changed; soldier on */
        if (uf == old_uf) {
            u->field_data[uf].len++;
            continue;
        }

        u->field_data[uf].off = p - buf;
        u->field_data[uf].len = 1;

        u->field_set |= (1 << uf);
        old_uf = uf;
    }

    /* host must be present if there is a schema */
    /* parsing http:///toto will fail */
    if ((u->field_set & ((1 << UF_SCHEMA) | (1 << UF_HOST))) != 0) {
        if (http_parse_host(buf, u, found_at) != 0) {
            return 1;
        }
    }

    /* CONNECT requests can only contain "hostname:port" */
    if (is_connect && u->field_set != ((1 << UF_HOST)|(1 << UF_PORT))) {
        return 1;
    }

    if (u->field_set & (1 << UF_PORT)) {
        /* Don't bother with endp; we've already validated the string */
        unsigned long v = strtoul(buf + u->field_data[UF_PORT].off, NULL, 10);

        /* Ports have a max value of 2^16 */
        if (v > 0xffff) {
            return 1;
        }

        u->port = (uint16_t) v;
    }

    return 0;
}

inline void
http_parser_pause(http_parser *parser, int paused) {
    /* Users should only be pausing/unpausing a parser that is not in an error
     * state. In non-debug builds, there's not much that we can do about this
     * other than ignore it.
     */
    if (CROW_HTTP_PARSER_ERRNO(parser) == HPE_OK ||
    CROW_HTTP_PARSER_ERRNO(parser) == HPE_PAUSED) {
        CROW_SET_ERRNO((paused) ? HPE_PAUSED : HPE_OK);
    }
    else {
        assert(0 && "Attempting to pause parser in error state");
    }
}

inline int
http_body_is_final(const struct http_parser *parser) {
    return parser->state == s_message_done;
}

inline unsigned long
http_parser_version(void) {
    return CROW_HTTP_PARSER_VERSION_MAJOR * 0x10000 |
    CROW_HTTP_PARSER_VERSION_MINOR * 0x00100 |
    CROW_HTTP_PARSER_VERSION_PATCH * 0x00001;
}

#undef CROW_HTTP_METHOD_MAP
#undef CROW_HTTP_ERRNO_MAP
#undef CROW_SET_ERRNO
#undef CROW_CALLBACK_NOTIFY_
#undef CROW_CALLBACK_NOTIFY
#undef CROW_CALLBACK_NOTIFY_NOADVANCE
#undef CROW_CALLBACK_DATA_
#undef CROW_CALLBACK_DATA
#undef CROW_CALLBACK_DATA_NOADVANCE
#undef CROW_MARK
#undef CROW_PROXY_CONNECTION
#undef CROW_CONNECTION
#undef CROW_CONTENT_LENGTH
#undef CROW_TRANSFER_ENCODING
#undef CROW_UPGRADE
#undef CROW_CHUNKED
#undef CROW_KEEP_ALIVE
#undef CROW_CLOSE
#undef CROW_PARSING_HEADER
#undef CROW_CR
#undef CROW_LF
#undef CROW_LOWER
#undef CROW_IS_ALPHA
#undef CROW_IS_NUM
#undef CROW_IS_ALPHANUM
#undef CROW_IS_HEX
#undef CROW_IS_MARK
#undef CROW_IS_USERINFO_CHAR
#undef CROW_TOKEN
#undef CROW_IS_URL_CHAR
#undef CROW_IS_HOST_CHAR
#undef CROW_start_state
#undef CROW_STRICT_CHECK
#undef CROW_NEW_MESSAGE

#ifdef __cplusplus
}
#endif
#endif
